203 lines
7.9 KiB
HTML
203 lines
7.9 KiB
HTML
<!DOCTYPE html>
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<html>
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<head>
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<meta name="viewport" content="width=device-width, initial-scale=1">
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<title>Incremental Tree</title>
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<meta name="description" content="Incrementally grow a tree as each node is expanded for the first time." />
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<!-- Copyright 1998-2017 by Northwoods Software Corporation. -->
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<meta charset="UTF-8">
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<script src="../release/go.js"></script>
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<script src="../assets/js/goSamples.js"></script> <!-- this is only for the GoJS Samples framework -->
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<script id="code">
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function init() {
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if (window.goSamples) goSamples(); // init for these samples -- you don't need to call this
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var $ = go.GraphObject.make; // for conciseness in defining templates
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var blues = ['#E1F5FE', '#B3E5FC', '#81D4FA', '#4FC3F7', '#29B6F6', '#03A9F4', '#039BE5', '#0288D1', '#0277BD', '#01579B'];
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myDiagram =
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$(go.Diagram, "myDiagramDiv", // must name or refer to the DIV HTML element
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{
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initialAutoScale: go.Diagram.UniformToFill,
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contentAlignment: go.Spot.Center,
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layout: $(go.ForceDirectedLayout),
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// moving and copying nodes also moves and copies their subtrees
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"commandHandler.copiesTree": true, // for the copy command
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"commandHandler.deletesTree": true, // for the delete command
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"draggingTool.dragsTree": true, // dragging for both move and copy
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"undoManager.isEnabled": true
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});
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// Define the Node template.
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// This uses a Spot Panel to position a button relative
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// to the ellipse surrounding the text.
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myDiagram.nodeTemplate =
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$(go.Node, "Spot",
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{
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selectionObjectName: "PANEL",
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isTreeExpanded: false,
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isTreeLeaf: false
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},
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// the node's outer shape, which will surround the text
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$(go.Panel, "Auto",
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{ name: "PANEL" },
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$(go.Shape, "Circle",
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{ fill: "whitesmoke", stroke: "black" },
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new go.Binding("fill", "rootdistance", function(dist) {
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dist = Math.min(blues.length - 1, dist);
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return blues[dist];
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})),
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$(go.TextBlock,
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{ font: "12pt sans-serif", margin: 5 },
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new go.Binding("text", "key"))
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),
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// the expand/collapse button, at the top-right corner
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$("TreeExpanderButton",
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{
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name: 'TREEBUTTON',
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width: 20, height: 20,
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alignment: go.Spot.TopRight,
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alignmentFocus: go.Spot.Center,
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// customize the expander behavior to
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// create children if the node has never been expanded
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click: function (e, obj) { // OBJ is the Button
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var node = obj.part; // get the Node containing this Button
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if (node === null) return;
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e.handled = true;
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expandNode(node);
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}
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}
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) // end TreeExpanderButton
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); // end Node
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// create the model with a root node data
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myDiagram.model = new go.TreeModel([
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{ key: 0, color: blues[0], everExpanded: false }
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]);
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document.getElementById('zoomToFit').addEventListener('click', function() {
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myDiagram.zoomToFit();
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});
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document.getElementById('expandAtRandom').addEventListener('click', function() {
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expandAtRandom();
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});
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}
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function expandNode(node) {
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var diagram = node.diagram;
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diagram.startTransaction("CollapseExpandTree");
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// this behavior is specific to this incrementalTree sample:
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var data = node.data;
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if (!data.everExpanded) {
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// only create children once per node
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diagram.model.setDataProperty(data, "everExpanded", true);
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var numchildren = createSubTree(data);
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if (numchildren === 0) { // now known no children: don't need Button!
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node.findObject('TREEBUTTON').visible = false;
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}
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}
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// this behavior is generic for most expand/collapse tree buttons:
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if (node.isTreeExpanded) {
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diagram.commandHandler.collapseTree(node);
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} else {
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diagram.commandHandler.expandTree(node);
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}
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diagram.commitTransaction("CollapseExpandTree");
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myDiagram.zoomToFit();
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}
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// This dynamically creates the immediate children for a node.
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// The sample assumes that we have no idea of whether there are any children
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// for a node until we look for them the first time, which happens
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// upon the first tree-expand of a node.
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function createSubTree(parentdata) {
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var numchildren = Math.floor(Math.random() * 10);
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if (myDiagram.nodes.count <= 1) {
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numchildren += 1; // make sure the root node has at least one child
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}
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// create several node data objects and add them to the model
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var model = myDiagram.model;
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var parent = myDiagram.findNodeForData(parentdata);
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var degrees = 1;
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var grandparent = parent.findTreeParentNode();
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while (grandparent) {
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degrees++;
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grandparent = grandparent.findTreeParentNode();
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}
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for (var i = 0; i < numchildren; i++) {
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var childdata = {
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key: model.nodeDataArray.length,
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parent: parentdata.key,
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rootdistance: degrees
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};
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// add to model.nodeDataArray and create a Node
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model.addNodeData(childdata);
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// position the new child node close to the parent
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var child = myDiagram.findNodeForData(childdata);
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child.location = parent.location;
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}
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return numchildren;
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}
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function expandAtRandom() {
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var eligibleNodes = [];
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myDiagram.nodes.each(function(n) {
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if (!n.isTreeExpanded) eligibleNodes.push(n);
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})
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var node = eligibleNodes[Math.floor(Math.random() * (eligibleNodes.length))];
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expandNode(node);
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}
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</script>
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</head>
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<body onload="init()">
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<div id="sample">
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<div id="myDiagramDiv" style="background-color: white; border: solid 1px black; width: 100%; height: 700px"></div>
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<p><button id="zoomToFit">Zoom to Fit</button><button id="expandAtRandom">Expand random Node</button></p>
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<p>
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This diagram demonstrates the expansion of a tree where nodes are only created "on-demand",
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when the user clicks on the "expand" Button.
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As you expand the tree, it automatically performs a force-directed layout,
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which will make some room for the additional nodes.
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</p>
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<p>
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The data for each node is implemented by a JavaScript object held by the Diagram's model.
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Each node data has an <b>everExpanded</b> property that indicates whether we have already
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created all of its "child" data and added them to the model.
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The <b>everExpanded</b> property defaults to false,
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to match the initial value of <a>Node.isTreeExpanded</a> in the node template,
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which specifies that the nodes start collapsed.
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</p>
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<p>
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When the user clicks on the "expand" Button, the button click event handler finds the corresponding
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data object by going up the visual tree to find the Node via the <a>GraphObject.part</a> property
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and then getting the node data that the Node is bound to via <a>Part.data</a>.
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If <b>everExpanded</b> is false, the code creates a random number of
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child data for that node, each with a random <b>color</b> property.
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Then the button click event handler changes the value of <b>Node.isExpandedTree</b>,
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thereby expanding or collapsing the node.
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</p>
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<p>
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Some initial node expansions result in there being no children at all.
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In this case the Button is made invisible.
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</p>
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<p>
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All changes are performed within a transaction.
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You should always surround your code with calls to <a>Model.startTransaction</a> and <a>Model.commitTransaction</a>,
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or the same methods on <a>Diagram</a>.
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</p>
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<p>
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The diagram's <a>Diagram.layout</a> is an instance of <a>ForceDirectedLayout</a>.
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The standard conditions under which the layout will be performed include
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when nodes or links or group-memberships are added or removed from the model,
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or when they change visibility.
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In this case that means that when the user expands or collapses a node,
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another force-directed layout occurs again, even upon repeated expansions or collapses.
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</p>
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</div>
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</body>
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</html>
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